808991 has 2 divisors, whose sum is σ = 808992. Its totient is φ = 808990.

The previous prime is 808981. The next prime is 808993. The reversal of 808991 is 199808.

It is a happy number.

808991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-808991 is a prime.

Together with 808993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (808993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404495 + 404496.

It is an arithmetic number, because the mean of its divisors is an integer number (404496).

2⁸⁰⁸⁹⁹¹ is an apocalyptic number.

808991 is a deficient number, since it is larger than the sum of its proper divisors (1).

808991 is an equidigital number, since it uses as much as digits as its factorization.

808991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 808991 is about 899.4392697676. The cubic root of 808991 is about 93.1782529525.

The spelling of 808991 in words is "eight hundred eight thousand, nine hundred ninety-one".